Left cylinder not running properly

[mustangGT90210]

Checked my valves the other day, exhausts are.... scary close to being at .00mm... So what would you guys reccommend for a test shim size? I'm going to order the tool and 2 shims, so what's a shot in the dark, good test size? I've accepted I'll probably have to redo it, but I want to try once and maybe get lucky lol

[adidasguy]

New shim size depends on what's in there now. If you need 0.05mm, then you need a shim about that much thinner than what's in there now.

There is no standard shim size.

You have to remove and measure what you have now then you can determine the new shim size. You will need calipers to measure. Most are not stamped with a size and those that were, it may be worn off.

[mustangGT90210]

Dangit. I'll have to give the dealer a call and see if they'll trade shims with me then

[adidasguy]

You have to do the math: if you have X clearance and need Y clearance and your current shim is Z then what size new shim do you need?

Z + X - Y = new shim

2.60 + 0.01 - 0.08 = 2.53
So you would go with a 2.50 (looser) or 2.55 (tighter)

There is a table in the service manuals to save you from doing the math.

many dealers swap shims if they have what you need. $1-$2 per shim.

[mustangGT90210]

So if I have a 2.60 shim, and a .01 clearance, going to a 2.55 shim will give me a .06 clearance, got it! I'm just waiting on parts now Update comes soon!

[tb0lt]

Even if you have already checkd the carbs, cleanthem again. Especially, the left pilot. Then, once you are done, clear it all over again. You have to be 100% sure that the left carb pilot and all the tiny circuits are clean and clear.

I ended up replacing a freaking head one to fix a non working left cyl only to realize the problem was the pilot circuit all along.

[mustangGT90210]

Even if you have already checkd the carbs, cleanthem again. Especially, the left pilot. Then, once you are done, clear it all over again. You have to be 100% sure that the left carb pilot and all the tiny circuits are clean and clear.

I ended up replacing a freaking head one to fix a non working left cyl only to realize the problem was the pilot circuit all along.

Turned out to be the carb diaphragm, I siliconed it and problem solved. WAiting on the new part to show up now to replace that rigged one